DV rack HDV or Broadcast monitor ?

[Wesley Wong]

What would be a better buy ? those Sony 14" 'D' tv broadcast monitors cost so much more than a comparatively larger screend laptop + DV rack , which seems like it can do more, barring the look of TFT screens.

Thanks for your inputs.

[Barry Green]

They're designed for two very different purposes, and, indeed, will give two very different looks, but not for the reasons you might suspect.

DV Rack does have an HD monitor module if you get the new "HDV PowerPack" upgrade. However, at today's computer processing speeds, you're not going to get full realtime display. At NAB it looked a little posterized, like maybe 15fps or so (but maybe the DV Rack guys will weigh in with exact numbers). As computers get faster that performance will increase, and eventually provide full realtime refresh rates.

A dedicated monitor will always show full realtime refresh rates. However, here's the kicker: with HDV, a monitor won't show you what your footage actually looks like! The new breed of affordable HD and HDV cameras all have uncompressed video output, so a live monitor hooked up to the component outputs will show you an HD image, but it won't show you what the post-compression footage actually looks like. This is especially important for HDV, with the potential for significant motion artifacts -- if you use a conventional monitor, you won't know whether your footage is artifacting or not. You can't see it in the LCD, and you can't see it on the monitor.

Where you *can* see it, is in the DV Rack monitor. DV Rack takes the footage after compression, so any compression artifacts, motion artifacts, etc. will be displayed on the DV Rack monitor.

DV Rack of course has many other pluses to it, such as the waveform, vectorscope, audio monitors and the direct-to-disk recorder. All of that combined make it a must-buy. But for monitoring, I think it's even more important for HDV users than it was for DV users... however, keep in mind that it doesn't give you full refresh rates on today's processors, so... it's not really a direct substitute for a genuine HD monitor.

For a fully professional shooting environment, you'd want both.

[Douglas Spotted Eagle]

As we see laptops with hardware mpeg decoders built into the video card, you'll see these rates run up. HDV Rack *should* give you real time feedback, depending on the system. I'm getting about 20 frames right now on a VAIO Pentium 4, gig of RAM. But if the video card has a decoder built into it, and they're now starting to hit the laptop world, this should climb to full framerate/preview size.

[Christopher C. Murphy]

Damn, I was about to invest in a PC laptop and get the HDV DV Rack. But, I forgot to think about actually real time viewing of HDV. It's not possible to use the laptop as a monitor? Ok, I need to re-think my purchase of a laptop.

[Douglas Spotted Eagle]

It's real-time, it just currently doesn't provide full framerate on most laptops.

[Christopher C. Murphy]

Well, without full frame rate it doesn't really sound usefull to me. I know it has the other componets though.

If the window is re-sized down to a smaller window...would that give faster frame rates??

[Wesley Wong]

Thanks for all the valuable input.

So Barry and Doug, a fast laptop and the HDV rack would genuinely be a little better than those 'd' TV widescreen broadcast motniors, but not by a mile, since you get slower refresh rates than actual 50i/60i fps . And those broadcast monitors that accept , say Sony Z1's video outputs thought component cables, will only give a compressed HDV look at full refresh rates, but doesn't show exactly what's ultimately recorded on the tapes then ?

Am I right ?

[Barry Green]

HDV Rack, as a total solution, would give you far more than just a monitor. I cannot overemphasize the usefulness of the disk recording feature alone -- it's incredible. And, it totally and completely removes any worry of HDV dropouts (1/2-second freeze-ups). If I could only have one or the other, I'd vote for HDV Rack.

However, the monitoring is not quite equivalent to a true HD monitor yet.

The output from a Sony Z1's component cables will only give an *uncompressed* look at full refresh rates, but will not show you what the HDV compression is doing to your footage. And that's an important distinction. If you're recording to tape (or to HDV Rack's hard disk, or to a FireStore) your footage is getting compressed, and the way MPEG compression works, that compression can be nearly transparent or it can be quite intrusive. You need to know what your footage really, really looks like, not just what an uncompressed version looks like on a component monitor, because if you're recording that footage, what it looks like on the analog outputs is, frankly, irrelevant. Only what gets recorded matters.

And the only way you're going to see what you're actually recording is through the firewire port -- whether through HDV Rack, or through some sort of firewire-to-analog converter... if someone made an HDV-to-analog-component converter (like a Miranda HDV-to-HD-SDI converter, but to analog component) then I think that would be a very valuable tool, that would let you view the post-compression footage on your analog monitor.

[Michael Maier]

Originally Posted by Barry Green

A dedicated monitor will always show full realtime refresh rates. However, here's the kicker: with HDV, a monitor won't show you what your footage actually looks like! The new breed of affordable HD and HDV cameras all have uncompressed video output, so a live monitor hooked up to the component outputs will show you an HD image, but it won't show you what the post-compression footage actually looks like. This is especially important for HDV, with the potential for significant motion artifacts -- if you use a conventional monitor, you won't know whether your footage is artifacting or not. You can't see it in the LCD, and you can't see it on the monitor.

Barry, that's also true with any camera right? The camera out and video out outputs were always before compression. The problem which HDV seems to be the extra compression, making it more risky. But if using the HDV Rack, at no full refreshing rates, won't it be hard to catch a 1/2 second freeze up and other glitches?

Sorry for bumping up an old thread, but I'm doing research on HDV and came across this one. I didn't want to start a new thread to ask a question I could ask here.

[Barry Green]

Barry, that's also true with any camera right? The camera out and video out outputs were always before compression.

Not necessarily. The original VX1000's analog output was traced and found to be post-compression, so what you saw on the monitor was what you'd get on the tape. Don't know about more-recent models.

The problem which HDV seems to be the extra compression, making it more risky.

HDV is by far the most-compressed digital video format yet, so compression artifacts are more likely with HDV. DigiBeta and MPEG-IMX and DVCPRO50 are much, much, much milder compression. DV has its share of artifacts, but in practical use I don't think it's ever really been an issue, regarding what-you-see-is-what-you-get. And, again, it may be that more DV cameras' analog outputs are also post-compression as well.

But if using the HDV Rack, at no full refreshing rates, won't it be hard to catch a 1/2 second freeze up and other glitches?

If using HDV Rack, there won't *be* any half-second freeze-ups. That's something that happens on the tape, and HDV Rack bypasses the tape, thus solving that problem. If you record to tape and also to the Rack simultaneously, then yes it's possible that the tape could still encounter such an error. But the freeze-up isn't a failing of the MPEG codec, it's the result of something going wrong in the actual recording on tape -- a dropout.

Where HDV Rack shines is that it shows you exactly what's going on that tape/disk. So if you have macroblocking, excessive mosquito noise, motion artifacting, resolution-softening, anything like that -- you'll see it on the HDV Rack monitor, vs. on the camera's analog outputs to a regular monitor where you won't see *any* of that stuff happening. It'll still be happening but the analog outputs don't let you see it, so if you monitor only with an analog/broadcast monitor, you won't really be seeing what you're really getting.

If your system's not fast enough, you won't see the full MPEG frame though. HDV Rack has a few "throttle controls" to keep the monitor display from using up too much CPU time, a circumstance that could lead to dropped frames on the hard disk recording. So if you really want to see the monitor in full resolution and see what-you-see-is-what-you-get, you'd need a reasonably powerful computer; SM recommends 3.2GHz or above for HDV monitoring.

[Boyd Ostroff]

Originally Posted by Barry Green

If using HDV Rack, there won't *be* any half-second freeze-ups. That's something that happens on the tape, and HDV Rack bypasses the tape, thus solving that problem.

Well I admit that I don't know anything about DV Rack specifically, but with any form of hard drive recording, isn't there always the chance that the disk/software/cpu will occasionally fail to keep up with the data stream and drop frames? For example, this happens with regular DV footage from time to time while capturing and printing to video, even with fast 7200 RPM drives and dual 2.5ghz G5 cpu's on the Mac.

[Ed Szarleta]

Anyone have a mobile unit with the GeForce 6600 to Go or 6800 to GO cards in them. Just wondering how the PureVideo hardware decoder improves performance on HDV Rack?

[Sean Hansen]

I have never personally had any dropped frames from dv to my pc's & laptop. Even after over 70 tapes this year alone. I saw a demonstration of dv rack and it's tools. Seems like a great option for those of us who carry our laptops and capture/edit on the fly. I would love to try the hdv version and down the road get it.

But I guess it also comes down to individual needs/preferences too. Some people already have those tools so don't need them? Thus a good monitor is their choice.

[Joe Carney]

Interesting, I have an HP Pavillion zd8K series laptop
3ghz P4 HT, 2meg L2 cache, 1 gig ram and the ATI X600 pcexpress video card with 128 meg of ram. It's supposed to have hardware mpeg decoding on it.
I know the mpeg and hdv mpeg(mt2) files I"ve played have looked outstanding, including the HD stuff I've downloaded from various camera test sites. Guess I should try to download a trial version and check it out. If thats possible.

[Ken Hodson]

I think it should be noted that HDVrack has an easier time with monitoring if you use the 720p HDV. Our P4 2.6 with 768mb handles it quite well. I use HDVrack on the laptop and svideo out to SD TV at the same time. Works great.
We use a firewire 800 card so I'm not sure if that plays into it or not?